Generally, inverters for power generators and power supplies use high voltage power semiconductor switches. Power generators and supplies may include devices such as solar panels, wind turbines, grid supplied motors, and uninterruptible power supplies (UPSs). Power semiconductor switches may include devices such as bipolar junction transistors (BJTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), insulated-gate bipolar transistors (IGBTs), and the like. During operation, these power switches may experience an overload condition, which may lead to an overpower condition such as an overcurrent, overvoltage, or over-temperature condition. If an overload condition occurs, damage for the power semiconductor switch may occur leading to destruction of the power semiconductor switch or damage to supplied elements, such as a load supplied by the power supply.
Thus, efforts exist to detect overload conditions, such as overcurrent conditions. Detecting overcurrent conditions may be done using low-voltage devices, such as integrated circuit (IC) devices, which protect the power switch from the overcurrent conditions. One technique for detecting overcurrent conditions involves directly measuring the output current of the switching network, such as with a half-bridge. Another technique for detecting overcurrent conditions involves implementing fast desaturation detection in the switch. During a current overload for a BJT or IGBT, the collector-emitter voltage VCE of the BJT or IGBT increases rapidly while the switch exits saturation, i.e., desaturates. Similarly, during a current overload for a MOSFET, increased currents will lead firstly to an increase of the drain-source voltage VDS of the MOSFET and then, due to further increasing of the current, the MOSFET will enter saturation. Measuring collector-emitter voltage VCE or drain-source voltage VDS is a direct way to determine that the switch has entered a current overload condition. However, semiconductor switches for power generators and supplies may operate at high voltages, and measuring collector-emitter voltage VCE or drain-source voltage VDS may present challenges for measurement using an IC.